Telephone test set



@11.2, 1923. 1,440,752. R. B. STO N E.

TELEPHONE TEST SET.

FILED SEPT. 9, 1919.

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nasngvrnnn, rnnnnssnn Application filed september 9, 1919. Serial No. 322,704.

To ali 'whom it may consom: y

Be it known that I, Roenn'r B. STONE, a citizen of the United States, residing at Nashville, in the county of Davidson and State of Tennessee, have invented certain new 4and useful Improvements in Telephone rl`est Sets; and l do hereby declare the following to be a full, clear, and exact descrip tion of the invention, such as will enable others skilled in the art to which .it appertains to make and use the same', reference being had to the accompanying drawings, and to the letters and figures of reference marked thereon, which form a part of this specification.

This invention relates to new and useful improvements in railway test telephone, and the object in view is to roduce a simple and. eiiicient device of this na ure a'ording means whereby a person may connect up with a telephone line intermediate stations for the purpose of sending or receiving messages at anJ1 station.

'Heretofore it has been the practice in apparatus of this nature to employ a testK set having a magneto generator which is necessarily of heavy weight and inconvenient to carry from place to place intermediate stations, and as a consequence maintainers frequently take chances on calling from a railroad station, while in the meantime it may be dirable for the home station or wire chief to get into communication with the maintainer in the event of any trouble de'veloping and neceitating being cleared up at once. The maintainer not having at hand an apparatus to cail in at an location around the line intermediate stations, a deflay necessarily ensues until communication can be had with the nearest station.

Itis the object of the present invention to produce a simple and eioient test set of light weight and which may be conveniently carried by the operator or maintainer for immediate use at any pole along the line. i

The invention comprises further details of construction, combination and arrang ment of parts which will be hereinafter fu ly 4 described, shown in the accompanying drawings and then specifically deined in the appended claim.

My invention is illustrated in the accompanying drawings which, with the numerals of reference marked thereon, form a part of this application, and in which:

Figure 1 is a side elevation of the test set,

ative parts of the apparatus an Figure 2 .is a front elevation of the same, and Figure 3 is a diagrammatic view showlng the wiring used in connection with my ap aratus.

eference now being had to the details of the drawings by numerals.:

1 designates a casing containin the operupon the upper end of which 1s mounted a receiver 2, and 3 designates a transmitter ositioned conveniently upon a lateral extension of. the

casing. Wlthin the casing 1 is located an insulation blo-ck 25, having connected there- 'to wires 26 and 27 by'binding'posts 26 and 27 respectively. To the binding posts 26 and 27 are connected the wires which terminate in the clips 2 8 and 29, forming the cord 30' by which the device is connected to the line when in use. The wire 26 connects through the wire 26 with the'switch blade 18, which is -in normal Contact with the switch blade 22 connecting thereby through the wire 22 with the wire 23 to the receiver 2, and through the .receiver 2 and wire y2li back to the wire 27 and the binding post 27 whereby when the several parts are in the position shown in the diagranunatic Figure 3, the receiver 2 thus connected is in circuit i wlth the line and the instrument'in condition to listen in. In this condition the instrument is not inl condition to talk through the transmitter 3. To accomplish the con-l nection of the linesV so that the transmitter 3 may be employed, the pushb-utton 31 is manipulated, throwing the switch blade 18 out of contact with the blade 22. and into contact with the blade 8, and by reason of the insulating spacer 17 also actuating the switch blade 16 to throw it into contact with the switch blade 14. The transmitter is now in a local circuit in which the wire 5 from the transmitter 3 leads to the primary winding of the induction coil 4, then through the wire 15 to the switch blade 16 and from the switch blades 16 and 14 throughthe wire 13 to battery 11, and through the wire 12 to the transmitter 3. The closing of this local circuit with the battery 11 in such circuit and the vibration of the transmitter by speaking induces in the induction coil a secondary current in the secondary winding, whereby i l current through the wire 7 is transmitted to the switch blade 8 and through the blade 18 and wire 26" to the resistance coil 19, then through the wire 21 to the point 21 From the point 21 a shunt is taken to the receiver through the wire 23 across the vreceiver to point 26X to the wire`26 and binding post 26',

through the line returning to the bindingl post 27 to the wire 27 to the point 27, and through the wire 27X, to the secondary lWinding of the induction coil. ln a plug ing in of the line, therefore, the receiver on y is in When, however, the manual key 31 is actuated, throwing both of the switch blades 16 and 18, the circuit is solchanged that the transimtter 1s now in its local circuit, inducing, the current to the receiver and to the line. v

What I claim to be new is:

A casing for a portable telephone test set carrying a transmitter and receiver, the casing comprising a tube having oncflat face, the tube compressed together at one end and bent to carry the transmitter, the receiver mounted on the .fiat face at the other end, the tube serving as a container for electrical elements and apertured to receive leads.

signature.

` ROBERT BURNS STONE.

circuit so that the'operato-r only listens in. lln testimony whereof l hereunto aix my 30 

